Two-Pion Intensity-Interferometry in Non-Central Collisions of Au + Au @ 1.23 A GeV

High-statistics π-, π- and π+, π+ HBT data for non-central Au + Au collisions at 1.23 A GeV, measured with HADES at SIS18/GSI, are presented. The three-dimensional emission source is studied in dependence on pair transverse momentum and beam energy. A tilt of the source with respect to the reaction plane is observed. The spatial extension and the tilt magnitude of the source decrease with transverse momentum. A clear charge-sign difference is observed for the spatio-temporal variances, but not for the tilt angle of the source. Derived geometrical and temporal parameters do well complement the trend over several orders of magnitude in beam-energy provided that consistent transverse momenta are selected.